Low-Threshold Multiwavelength Plasmonic Nanolasing in an “H”-Shape Cavity

Multiwavelength plasmonic nanolasers are central to the quest for ultradense and versatile photonic integrations. However, the insufficient optical feedback and mode selection strategies result in a high lasing threshold and multi-mode operation with limited spectral purity and stability. Here, a multiwavelength near-infrared plasmonic nanolaser with high mode purity by leveraging a nontrivial “H”-shape plasmonic cavity is demonstrated. The nanolaser is constructed by inserting InGaAs/GaAs multi-quantum-disk (MQD) nanowires into a metallic Fabry-Perot cavity consisting of a pair of Ag nanowires positioned on an ultrasmooth Au film. The design is endowed with strong optical feedback to enhance the energy transfer between the exciton and plasmon, rendering a significant reduction of the lasing threshold. More importantly, the “H”-shape cavity is featured with a large flexibility in tuning the resonance wavelength, where multiwavelength lasing with the virtues of single-mode is realized at room temperature. The results make a crucial step toward near-infrared multiwavelength plasmonic nanolasers and open up exciting opportunities for applications such as ultracompact photonic integrated circuits and high-throughput biochemical sensing.